全文获取类型
收费全文 | 489篇 |
免费 | 40篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 6篇 |
综合类 | 1篇 |
化学工业 | 184篇 |
金属工艺 | 9篇 |
机械仪表 | 11篇 |
建筑科学 | 9篇 |
能源动力 | 19篇 |
轻工业 | 49篇 |
无线电 | 32篇 |
一般工业技术 | 56篇 |
冶金工业 | 25篇 |
原子能技术 | 1篇 |
自动化技术 | 128篇 |
出版年
2024年 | 2篇 |
2023年 | 15篇 |
2022年 | 31篇 |
2021年 | 72篇 |
2020年 | 23篇 |
2019年 | 19篇 |
2018年 | 27篇 |
2017年 | 19篇 |
2016年 | 25篇 |
2015年 | 14篇 |
2014年 | 29篇 |
2013年 | 27篇 |
2012年 | 29篇 |
2011年 | 35篇 |
2010年 | 27篇 |
2009年 | 27篇 |
2008年 | 27篇 |
2007年 | 11篇 |
2006年 | 13篇 |
2005年 | 8篇 |
2004年 | 9篇 |
2003年 | 4篇 |
2002年 | 3篇 |
2001年 | 5篇 |
2000年 | 5篇 |
1999年 | 1篇 |
1998年 | 6篇 |
1997年 | 4篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1992年 | 2篇 |
1988年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1976年 | 2篇 |
1971年 | 1篇 |
排序方式: 共有530条查询结果,搜索用时 31 毫秒
51.
52.
Antonio Evidente Anna Andolfi Alessio Cimmino Sonia Ganassi Claudio Altomare Mara Favilla Antonio De Cristofaro Silvia Vitagliano Maria Agnese Sabatini 《Journal of chemical ecology》2009,35(5):533-541
We report the effects of some bisorbicillinoids isolated from biomass of the fungus Trichoderma citrinoviride on settling and feeding preference of the aphid Schizaphis graminum. Purification of the fungal metabolites was carried out by a combination of column chromatography and thin-layer chromatography
using direct and reverse phases. Chemical identification was performed by spectroscopic methods including nuclear magnetic
resonance and mass spectrometry. The identified bisorbicillinoids appeared to be bislongiquinolide, its 16,17-dihydro derivative,
trichodimerol, and dihydrotrichodimerol. A feeding preference test with alate morphs of S. graminum was used to identify the active fractions. Among the four bisorbicillinoids, dihydrotrichodimerol and bislongiquinolide influenced
aphid feeding preference, restraining specimens from settling on leaves treated with metabolites. Taste neurons sensitive
to these compounds, particularly to bislongiquinolide, were located on tarsi of the S. graminum alate morphs. 相似文献
53.
Antonella Gori Cecilia Brunetti Luana Beatriz dos Santos Nascimento Giovanni Marino Lucia Guidi Francesco Ferrini Mauro Centritto Alessio Fini Massimiliano Tattini 《International journal of molecular sciences》2021,22(15)
Carotenoids and phenylpropanoids play a dual role of limiting and countering photooxidative stress. We hypothesize that their “antioxidant” function is prominent in plants exposed to summer drought, when climatic conditions exacerbate the light stress. To test this, we conducted a field study on Phillyrea latifolia, a Mediterranean evergreen shrub, carrying out daily physiological and biochemical analyses in spring and summer. We also investigated the functional role of the major phenylpropanoids in different leaf tissues. Summer leaves underwent the most severe drought stress concomitantly with a reduction in radiation use efficiency upon being exposed to intense photooxidative stress, particularly during the central hours of the day. In parallel, a significant daily variation in both carotenoids and phenylpropanoids was observed. Our data suggest that the morning-to-midday increase in zeaxanthin derived from the hydroxylation of ß-carotene to sustain non-photochemical quenching and limit lipid peroxidation in thylakoid membranes. We observed substantial spring-to-summer and morning-to-midday increases in quercetin and luteolin derivatives, mostly in the leaf mesophyll. These findings highlight their importance as antioxidants, countering the drought-induced photooxidative stress. We concluded that seasonal and daily changes in photosynthetic and non-photosynthetic pigments may allow P. latifolia leaves to avoid irreversible photodamage and to cope successfully with the Mediterranean harsh climate. 相似文献
54.
Alessio Zandona Bernd Rüdinger Joachim Deubener 《Journal of the American Ceramic Society》2021,104(2):1146-1155
Glass powder samples of cordierite composition (doped with 8 mol% TiO2) were heat-treated to produce a series of increasingly SiO2-enriched Mg-bearing quartz solid solutions (Qss). The obtained materials were then analyzed by X-ray diffraction: Rietveld structural refinements revealed that Mg-bearing Qss phases possess trigonal symmetry and a compositionally dependent intermediate structural arrangement between those of low and high quartz. High-temperature diffraction measurements were performed up to 700°C to characterize the thermal expansion behavior of the crystals. At SiO2-rich compositions, a reversible high-to-intermediate inversion of the quartz structure is observed, which shifts with increasing stuffing to lower temperatures than the conventional 573°C for pure quartz. Similarities and differences to the better-established Li-bearing Qss are discussed in the text. 相似文献
55.
Luca Pezzato Leonardo Bertolucci Coelho Rachele Bertolini Alessio Giorgio Settimi Katya Brunelli Marjorie Olivier Manuele Dabal 《工业材料与腐蚀》2019,70(11):2103-2112
Plasma electrolytic oxidation (PEO) coatings were produced on AZ80 magnesium alloy in a solution containing silicates and phosphates and working at high current densities with short treatment times. The effect of a sealing treatment in boiling water on corrosion and mechanical properties of the coatings were investigated. Moreover, the corrosion mechanism of the samples with and without the sealing treatment was evaluated. The microstructure of the coatings was characterized with scanning electron microscope observation and X‐ray diffraction analysis. The mechanical properties were evaluated with nanoindentation tests and the corrosion resistance was studied by potentiodynamic polarization, electrochemical impedance spectroscopy, and scanning vibrating electrode technique. The results showed that the sealing did not influence the microstructure and the mechanical properties of the samples and instead produced a remarkable increase in the corrosion resistance. The crevice corrosion, present in the sample without the sealing, was avoided with the treatment in boiling water. 相似文献
56.
Elisabeth Wyart Laure B. Bindels Erica Mina Alessio Menga Serena Stanga Paolo E. Porporato 《International journal of molecular sciences》2020,21(22)
Cachexia is a complication of dismal prognosis, which often represents the last step of several chronic diseases. For this reason, the comprehension of the molecular drivers of such a condition is crucial for the development of management approaches. Importantly, cachexia is a syndrome affecting various organs, which often results in systemic complications. To date, the majority of the research on cachexia has been focused on skeletal muscle, muscle atrophy being a pivotal cause of weight loss and the major feature associated with the steep reduction in quality of life. Nevertheless, defining the impact of cachexia on other organs is essential to properly comprehend the complexity of such a condition and potentially develop novel therapeutic approaches. 相似文献
57.
Nicola Alessio Domenico Aprile Salvatore Cappabianca Gianfranco Peluso Giovanni Di Bernardo Umberto Galderisi 《International journal of molecular sciences》2021,22(6)
During their life span, cells have two possible states: a non-cycling, quiescent state (G0) and a cycling, activated state. Cells may enter a reversible G0 state of quiescence or, alternatively, they may undergo an irreversible G0 state. The latter may be a physiological differentiation or, following a stress event, a senescent status. Discrimination among the several G0 states represents a significant investigation, since quiescence, differentiation, and senescence are progressive phenomena with intermediate transitional stages. We used the expression of Ki67, RPS6, and beta-galactosidase to identify healthy cells that progressively enter and leave quiescence through G0-entry, G0 and G0-alert states. We then evaluated how cells may enter senescence following a genotoxic stressful event. We identified an initial stress stage with the expression of beta-galactosidase and Ki67 proliferation marker. Cells may recover from stress events or become senescent passing through early and late senescence states. Discrimination between quiescence and senescence was based on the expression of RPS6, a marker of active protein synthesis that is present in senescent cells but absent in quiescent cells. Even taking into account that fixed G0 states do not exist, our molecular algorithm may represent a method for identifying turning points of G0 transitional states that continuously change. 相似文献
58.
Stefany Castaldi Claudia Petrillo Giuliana Donadio Fabrizio Dal Piaz Alessio Cimmino Marco Masi Antonio Evidente Rachele Isticato 《International journal of molecular sciences》2021,22(7)
In recent decades, intensive crop management has involved excessive use of pesticides or fertilizers, compromising environmental integrity and public health. Accordingly, there has been worldwide pressure to find an eco-friendly and safe strategy to ensure agricultural productivity. Among alternative approaches, Plant Growth-Promoting (PGP) rhizobacteria are receiving increasing attention as suitable biocontrol agents against agricultural pests. In the present study, 22 spore-forming bacteria were selected among a salt-pan rhizobacteria collection for their PGP traits and their antagonistic activity against the plant pathogen fungus Macrophomina phaseolina. Based on the higher antifungal activity, strain RHFS10, identified as Bacillus vallismortis, was further examined and cell-free supernatant assays, column purification, and tandem mass spectrometry were employed to purify and preliminarily identify the antifungal metabolites. Interestingly, the minimum inhibitory concentration assessed for the fractions active against M. phaseolina was 10 times lower and more stable than the one estimated for the commercial fungicide pentachloronitrobenzene. These results suggest the use of B. vallismortis strain RHFS10 as a potential plant growth-promoting rhizobacteria as an alternative to chemical pesticides to efficiently control the phytopathogenic fungus M. phaseolina. 相似文献
59.
In this paper, we examine the value of investing in energy-efficient household appliances from both an energy system and end-user perspectives. We consider a set of appliance categories constituting the majority of the electricity consumption in the private household sector, and focus on the stock of products which need to be replaced. First, we look at the energy system and investigate whether investing in improved energy efficiency can compete with the cost of electricity supply from existing or new power plants. To assess the analysis, Balmorel, a linear optimization model for the heat and power sectors, has been extended in order to endogenously determine the best possible investments in more efficient home appliances. Second, we propose a method to relate the optimal energy system solution to the end-user choices by incorporating consumer behaviour and electricity price addition due to taxes. The model is non-exclusively tested on the Danish energy system under different scenarios. Computational experiments show that several energy efficiency measures in the household sector should be regarded as valuable investments (e.g. an efficient lighting system) while others would require some form of support to become profitable. The analysis quantifies energy and economic savings from the consumer side and reveals the impacts on the Danish power system and surrounding countries. Compared to a business-as-usual energy scenario, the end-user attains net economic savings in the range of 30–40 EUR per year, and the system can benefit of an annual electricity demand reduction of 140–150 GWh. The paper enriches the existing literature about energy efficiency modelling in households, contributing with novel models, methods, and findings related to the Danish case. 相似文献
60.